Anyone who knows the LED dimming power supply industry knows that it has two completely different dimming methods, namely phase-modulated dimming and cutting-edge dimming. The conduction angle of the wave is used to change the sine waveform, and then the effective value of the communication current is changed to achieve the purpose of dimming, also known as chopper dimming. Phase-modulated dimming includes two types of leading edge phase manipulation and trailing edge phase manipulation (also known as front-cut and back-cut).
The leading edge dimming of the LED dimming power supply adopts a thyristor circuit, and the trailing edge dimming adopts a triode circuit, and the dimmer chops the input voltage waveform.
In fact, the leading edge is chopped in front, that is, it starts from the communication phase 0, the input voltage is chopped, and there is no voltage input until the thyristor is turned on. The trailing edge dimming is similar, starting from a phase turn off and turning on until 180 degrees.
Leading-edge dimmers have the advantages of high conditioning accuracy, high efficiency, small size, light weight, and simple long-distance operation. They dominate the market, and most manufacturers' products are of this type. Leading edge phase control dimmers usually use thyristors as switching devices, so they are also called thyristor dimmers.
Back-edge dimming: MOS/IGBT technology with zero-crossing on and trailing-edge off, which solves the problem of grid disturbance and noise. The soft-start and soft-shut-off technology used in the dimming actuator avoids the thermal shock of the LED filament
and further extends the life of the lamp.